Dualistic cab signal and automatic train-control system



Dec.f18 ,1923.

J. w. Bul-:LL

DUALISTIC CAB SIGNAL AND AUTOMATIC TRAlN CONTROL SYSTEM 3 Sheets-Sheet 1Filed Sept. 14

Dec. 18, 1923. 1,478,101

J. W. BUELL DUALISTIC CAB SIGNAL AND AUTOMATIC TRAIN CONTROL SYSTEMFiled Sept. 14 1921 5 Sheets-Sheet 2 Dec. 18 1923.

J. W. BUELL DUALISTIC CAB SIGNAL. AND AUTOMATIC TRAIN CONTROL SYSTEM 3Sheets-Sheet 3 A vvvvvvvvvvl Filed Sept. 14

Patented Dec. 18, 1923.

UNITED STATES PATENT OFFICE.

JOSEPH WHITMAN BUELL, 0F IVASHINGTON, DISTRICT OF COLUMBIA; WANDA A.BUELL, EXECUTRIX OF SAID JOSEPH WHITMAN BUELL, DECEASED, ASSIGNOR TOBUELL SIGNAL AND TRAIN CONTROL COMPANY, INCORPORATED, A CORPORATION OIFVIRGINIA.

DUALISTIC CAB SIGNAL AND AUTOMATIC TRAIN-CONTROL SYSTEM.

Application led September 14, 1921.

To all whom t 'may concern Be itl known that I, JOSEPH VHITMAN Buma., a.citizen of the United States, residing at the city of Vashington, in theDistrict ot Columbimhave invented certain neiv and usetul Improvementsin a Dualistic Cab Signal and Automatic Train-Control System,"ot' whichthe following is a speciiication.

This invention relates to a dualistic cab signal and automatic traincontrol system, that contemplates combining the general type ot' systemdisclosed in reissue patent, numbered 14,676, dated June 24th, 1919,with that type oit system disclosed in my (fo-pending United Statesapplication for Letters Patent, serial numbered 452,695 and tiled March16th, 1921.

Before dealing with or describing the actual system and apparatus, agood deal of ground will be cleared if certain aspects ot the inventionare first dealt With in more or less general terms.

In order tounderstand the nature and scope ot the present invention`with reference to its i'uiulamental characteristics, it will first beconsidered in relation to the principle of arrangement ot the circuitsandl control elements, as a means ot eiliecting a true combination.

In this general class o'' devices, it necessary to employ onl alocomotive, an electroniagnet governing means for controlling a signalgiving device and normally holding closed an air vent in the brakesystem, as long as current `flows through said magnet and upon thefailure tliercot to cause the production ot a signall and theapplication oi the air brakes.

One ot the main olljections to the employmeut ot a singin system. oitcontrivances a s magnet 'rovcrning means and the tract,v apparatus itscontrol and operatimi, has been that vfhen one of the members oi: theysystem becomes deranged it necmirily incapacitates the whole systoiu anda locomotive thus equipped has to proceed throughout the rest ot its runwith sole reliance on the roadside signals.

The present invention therefore contemplates multiple control andoperation ot the magnet governing means, by the establishment andinterruption of the current conditions,

Serial No. 500,673.

flowing through said magnet by reason of the joint control or effect ofa composite or duplicate means that is interposed between said magnetand the respective track circuits encountered.

To the end of providing `a dualistic or composite system, one branchithereof is arranged in operative relation to said electro-magnet andcomprises two normally inter-linked circuit members, Working on theclosed circuit principle, one ot' which includes said electro-magnet,While the other is brought into direct union With the all rail trackcircuit for control thereby at tratiic control points,V said controlbeing et- :t'ected in this branch ot the system by the introduction andWithdrawal of a point of resistance, in the track connected circuit,under the iniuence' of a safety shunt controlled by said track circuit.y

The other branch of said rdualistic system contemplates the employmentot' a controlling and operating apparatus, in which one clementcomprises a comparatively slow acting mechanically operated means, suchas a circuit breaker, controlled in its movement by a shoe engaging witha ramp, and which serves to positively interrupt the above mentionedcircuits at such points, every time said circuits pass those points,were, provision not made, under safety :tor introducing momentarily intothe combination, a normally incoluplete circuit by closing the sameunder the influence oi? ay second safety shunt and the controlling trackcircuit, to quickly ei'l'ect a shunt or compensating pathway acrossthose portions ot the interlinked circuits about to be broken by themechanically operated means, to thereby preserve the in-y delay.

ggg nec/arci By reason of such a principle of circuit and controlarrangement there is provided a true combination that secures the mostperfect mutual dependence or the means involved, as well as alfording atwo-fold plan of control and loperation both on the locomotive and thetrack at trafhc control points, that acts on a common mechanism, to wit,the electro-magnet governing means and which is governed by the controlot a given track circuit.V

The objection ordinarily offered to the employment ot an open circuitmeans in this art, is that a broken `conductor might continueundetecteifl and result in a danger giving condition. ln the presentinvention, however, in that branch of the system employing a normallyopen control circuit provision is made in toe event of a conductorthereol.3 becoming broken, or' relying upon the mechanically operatedmeans or circuitbreaker for producing a danger indication and theapplication of the brakes, thereby revealing the failure or' 'the brokenconductor on the side out safety.

F or the successful employmentot duplicate electrical means or agencieson a loco'- inotive, it should be designed so that the derangement ofone circuit member will not cause the derangernent of the other circuitmember, while both should be protected 'from injurious effects due to aclgrounding7 of the head-light circuits on a locomotive.

Therefore it is a further object ot the present invention to so combine`he co-ordinate circuit members ot the system, by making one oit themnormally activo., while the other remains inactive until it reaches atraffic control point, where under `rtety conditions, it is renderedactive but ii'or the moment, so that in the event ot one ot the circuitmembers becoming grounded7 it cannot dangerously atleet the othercircuit in inber because the fugitive current therefrom would simplyreinforce that oit the other circuit member and aid in. its tunctimiing.

A li'urther object of the present invention is to increase thei'irecautionary measures tor safety by providing on tour occasions, in agiven block or section, 'for Athe transmission from the trackl oit' acontrol or opel"- ative impulse to the apparatus on the locomotive, inaccordance with the condition ot the block ahead, as well as provi dingunder danger conditions .for the reduction of speed and gradual.stoppage of the train, by inaugurating a progressive service applicationof the air brakes within braking distance of the block ahead andcontinuing the brake application in the manner or natural order thatwould ordinarily be followed by an engineer in the face of danger.

It is further an object of the present invention to depend on electricper-,ver that comprises two traveling sources of electric energy,carried by the locomotive; the current from said sources may or may notdii"- ter in character, and 'to that end to employ a low voltage sourceof electric current, as a small storage battery in connection with oneportion of the dual system, and limiting it to its proper and economicalfield ot useiulness in supplying current to low voltage signal lamps andelectro-magnets, and to utilize, intermittently and n'ioinentarily, inthe normally inactive circuit member, under sa'liety conditions, when itis completed, a higher ,f'oltage current, that is preferably furnishedby the head-light turbo-generator, upon such occasions, therebyreducing` with vast economy the cost ot the power liact r, over the planthat depends upon current collection from track sources, at every blocksection along the line.

Electrical apparatus carried on a locomotive is subjected to heavy andvibration and the electrical conductors employed in conduits thereon donot have sutlicient insulation strength to withstand the wear due 'tothe effects of and vibration, for any great length ot time.

further object of this invention is to provide a suitable and reliablemeans tor revealing the insulation breakdown and grounding of conductorsin any circuit eniployed in this system, which is a matter olli vitalconcern in a system ot this kind.

Another obj` ect ot the present invention to provide a system having theabove; noted characteristics, which shall, while being` relativelysimple as regards its parts and their arrangement, require but smallcost to install and maintain it in operative condition, while at the sawie time it is certain and positive as regards its operation.

Those objects and tentures olI my invention which have not beenparticularly and separately mentioned in the it'oregoing preamble willclearly zuipear in the lig; olt he iollowii'igi; more detaileddescription oli my invention embodied in the combined subsystems, whichl have illustrated in the accompanying drawings.

As the present descrii'ition ot the dualistic system of train controldoes not relate so much to the structure ot the operating` mechanism asto the organization and inauucr ot control ol the circuits involved,such means will be mostly shown diaerammatically in the accompanyingdrawings.

llelierring to the drawingsfllliguro l, is a general circuit diagrannillustrating both circuit members oit the composite system united inworkingr relation to each other, when brought into operative relationwith a trailic controlling point.

Figure 2, shows an enlarged and detl vierv of coils 'lL-8, of the magnetgever means, and the circuit connections thereoflull E rig Figure 3,illustrates diagrammatically one form 'of track equipment required atthe home and approach points, respectively, on a double track line.

Figure 4t, shows a modified form of track equipment.

Figure 5, illustrates the structure provided in the truck insulation andthe circuit arrangements depended upon to reveal insulation breakdown inthe truck insulation and that of the conductors leading thereto.

Figure 6, shows an enlarged view of coils 7 8, of the governing magnet,illustrating the manner of employment of a second armature thereon forrevealing failure of coil 8.

Like characters of reference indicate corresponding parts in the severalfigures, while the arrow in Figure 1, shows the normal direction oftraffic for such an equipped line.

The purely electric branch of the dualistic system, constituting theinstant. invention, is generally the same, structurally and operativelyconsidered, as that described in the reissue patent aforesaid, and maybe briefly described as follows:

Referring to Fig. 1 of the dawings, 1", r represent the rails of thetrack, which is divided into sections or blocks by the usual insulatingjoints y', j', each section including a source of current T, bridgingthe rails at the remote end, and a relay TR bridging the rails at theentrance or near end oli the section, each relay being normallyenergized and the armature thereof closing a loop w, w', of negligibleresistance. bridging the insulated joints between the rails of adjacentblocks or sections. As indicated, the current Supply for the trackcircuit of each block or Section comprises a transformer T connectedwith mains TL, which supply alternating current from a `generator orgenerators located conveniently to the roadway, thereby eliminating thetrouble and expense of maintaining local track batteries in cach block.

Mounted on the locomotive are the control and working circuits, withtheir appropriate translating devices, supplied -from acommon battery 6,'the control circuits; having coils 7 and S of the differential relayDR, which latter controls the working circuit, being indicated byreference let` s and B, respectively: the working circuit, iu-

cluding the valve holding magnet VHM, isv

represented b v reference letter C; and the signal` or indicatingcircuit by D, the several circuits A., B, C and D being connected inparallel 4with common battery 6 carried by the locomotive.

Circuit A starts from the battery 6 and passes -bv way of wire 6*, loopwire Z, circuit braker B, loop wire Z, wire Q3 to forward truckFT, railr, loop fw, ce', including ar! mature ofrelay- TR, rail 1 ofprecedingblock, rear Wheels A2 to the frame of the locomotive, indicated bydotted line A3, to conductor f grounded on the engine frame at fc, coil7, wire 24, and wire -back to the battery 6. This particular circuit iseffective when the forward insulated truck FT is entering one block,such as X, and the other wheels of the locomotive occupy the rails inthe preceding block, such as Y, when the forward block X is clear. lVhenthe locomotive iswholly within a given block and the latter' is clear,the circuit A will be closed between the insulated forward truck FT andthe driving wheels of the locomotive by way of the rails r, r', as willbe understood.

The circuit B is follows: battery 6, wire 6*, wire 20, includingnormally closed push button pb, coil 8 of relay DR, wire 22, and wire6--back to the battery. A loop in this circuit, around the push buttonpb, formed by wires Cs and C, includes an air operated circuit breaker92, controlled by the air release during the application of the brakesand also the contacts of a speed governing means 95 to effeet therequired reduction of the speed oit the train after the air is released,before the system may be restored, by operating the push button pb.

Circuit C, which controls the valve holding. magnet VHM, is from battery6, wire 6*, loop wire Z, circuit breaker CB', loop wire il', wire 13,stationary contact 10, armature Contact` 9, armature 12 and frame l2 ofrelay DR, wire 19, coils of valve holding magnet VHM, in parallel, wire14, resistance R', wires 15 and -back to the battery.

'The circuit. D, which energizes the electric lamps L, or equivalentsignalling or indicating apparatus` includes wire 6*, wire 1S, lamps L,in parallel, wire 16, resistance R', wires 15 and G-to battery 6.

The system, as thus far described, is generally the same as that of thereissue patent aforesaid' in structural arrangement and mode ofoperation, the only'material variations therefrom being the inclusion ofthe loop wires Z, Z. and the normally closed circuit breaker CB in thecircuits A and (fl, aud the loop (lg, C'l around the push button p7) incircuit B, which latter controls coil 8 of relay DR. which loop includesthe air operated circuit breaker 92 and the speed governor controlledcircuit breaker 95, which two circuit breakers prevent thereenergization of the coil S andL the restoration of the system by theengineer operating push button pb, until the air brakes have been.applied and the speed of the train reduced to a predeterminedL point.

In the diagrammatic illustration of Fig. 1 vof the drawing, thelocomotive is shown as entering an unoccupied blockV` or section: X,

ture l2 will be attracted by coil 7 and the circuit C will beinterrupted contacts 9 and jlU, thereby deenergizing the valve holdingmagnet, ctfecting an application 0i: the brakes and the r 'sing of thecurrent value in the sigiial lamps L to bring them to brightincandescence.

As soon as the circuit ol coil 8 is restored, armature 12 will beimmediately attracted by the core of the coil to again close thecontacts 9 and 10, as the normal pull of the core ot the coil S on thearn'iature l2 will exceed the-attractive force of the core ot' coil 'i'.The deenergization ot coil 7 will `not affect armature 12, which willremain in position to close contacts 9 and 10, so long as coil 8 isenergized.

As was the case in the system described in the reissue pftentaforesaid,-the resistance R in the common section or' theparallel circuits C and Dis so adjusted that the lamps L will normally burn at low incandescence,thus serving as a telltale signal that gives constant evidence ot' theintegrity ot' the circuits and the condition of this portion ot thesystem. lllhen, however, the circuit C, which controls the valve holdingmagnet, is interrupted, the value ot the current in circuit l) will riseand bring the lamps to bright incandescence, thereby indicating a dangercondition. v

Because of the low internal resistance ot circuit A, including coil 7,and the employnicntot the bridge wire (il) between circuits .A and B,the system will func-tion reliably when the resistance in the insulatedjoints olI the track, or in a leakage pathway about said joints, is aslow as ft/l0 or" one ohm, and long before suoli alow resistance isreached, the loop fw, w', will, by reason ol? .overlapping relation withrespect to the Joint, short-circuit either the track relay TR in thecorresponding block, such as or the source of electric energy in theadjacent block Y, according to which of the rail joints or y" breaksdown to the mai"- ginal resistanceindicated.

ln order to limit or nullify the ei'l'ect O'lf any Yforeign directcurrent,flowing Vfrom one track section by way of loop fm, w to theadjacent section or block, on the track relay TR in the latter section,an impedance coil z' is bridged across the terminals ot the track relay,as indicated in Figs. l and 45.

It is obviously essential that the iront truck of the locomotiveequipped with the apparatus, as Vhereinbefore described, must becarefullyl and completely insulated from the other portions ofthel'ocomotive, and an effective means to this 'end is :illustrated inFig. 5, in which FT indicates, diagrammatically, the lower centerbearing casting forming' part ot the truck. The insulating meansconsists of a'series ot alternate'fiber cach other and in the recessinthe center bearing casting of the truck. This form of insulation maybe applied readily to k'the standard types 'of locomotives 'withoutkeeping the latter out of commission for any material length of time andhave proven entirely effective under the most trying trafic conditions'.llheside'walls` 'of the liber cups I are preferably extended 'verticallyabove the upper edges of themetallic cups M, so as to prevent theelectrical bridging 0l the cups M, M by thelodgment oi2 any foreignmetallic substance thereon.

ln order to clearly indicate the dualplan oi control and operation ofthecircuitsA and C, involving the insulated truck circuit on the onehand., and the ramp system-on the other, so that the two portions of thesystem will function simultaneously, or either will perform its normaloperation in case ot failure of the other, Vthe rampV controlled portionof the system and its association with the purely electric controlledportion ot the system will now be described.

is hereinbefore indicated, the circuits A and C each include a branch orloop, com-` prising wire Z, circuit breaker CB, and wire Z, the circuitbreaker serving to open and close the circuit between the loop sections,Z and Z. The circuit breaker CB" comprises a reciprocatory stem, havingheads on its` opposite ends, the upper head serving to close the loopcircuit Z, Z through a contact plate mounted on the support throughwhich the stem reciprocates, the wire Z'being connected to thestationarymember or plate of the circuit breaker and ther wire Z to thereciprocating stem. The movable and sta-` tionarycontacts of thecircuit' breaker are normally held in contact by a helical vspring Sesurrounding the stem. Likewise mounted for reciprocatory movement'andinsu"- lated from the engine frame, is ay shoe S, having an upwardlyextending stem de, which is normally forced downward or toward the trackby means of a helical spring The shoe S s surrounding the stein (Za. isso disposed as to engage ramps, such as t, R mounted on the side of thetrack, which ramps have their upper or contacting surfaces of anticlinalform, so that, when the shoe engages the upper face of the ramp, it willmove upwardly and downwardly in its traverse of the ramp,l therebyeli'ecting the successive opening and closing of the circuit breaker CBas each ramp is passed, the stem Za of the shoe S engaging the stem (ZZ)4of the circuit breaker so that, when the shoe is moved upwardly thecircuit breaker is moved in the same direction and when the shoe returnsto its normal position, after disengaging a ramp, the circuit breakerwill also automatically return to its normally closed position'.`Preferably, the

ill)

upper end of the shoe S is rated from the lower end breaker CB by asutiicient distance to et tect a short delay between the initialengagement or the shoe with a ramp and the opening ot the circuitbreaker CB. i

Preferably, each block or section is provided with two ramps R, lt, theupper conducting surface or each being connected in series with a wireTLO, one end ot which terminates in a contact Z1, which normally closedby the armature ot track relay thereby connecting ramp track loon'ill-i5() with the rail r of the adjacent block oy way of the loopsection w. I

Electrically connected with the shoe is al conductor 50, the other endot which is attached to the positive terminal ot a source ofelectricity, preferably the generator G, which supplies current to thehead-lightn The other terminal or the generator G is connected to aconductor, wound about the insulated conductor 50 and parailelinglj thesame in a reverse loop, to constitute an in sulation lbreak-downindicator,A as will be hereinafter described, the so-called detectorloop beingr indicated by wires (Z and al. The 'free end of the detectorwire d is connected to an electro-magnet the other terminal of which isconnected to a wire m providedL with a terminal contact n, normallyengaged by the armature m ot an electro-magnet or relay TM, the otherend oit said armature being grounded at G on the locomotive frame.

The circuit, as thus described, constitutes the so-called test orpick-up circuit, which is completed each time the shoe S engages a ramp,the complete circuit, under satetf-,r conditionsr` being as follows;from the positive pole ot generator G, through conductor 50, shoe S,surface conductor et ramp or R, loop TLO, contact ZL, armature oi trackrelay TR, track loop section w, rail normally sepaot the circuit 12driving` wheel l2 ot' the locomotive, the ce to Athe ground G ou thetrame,

armature tu, contact a, conductor m, map;- net lll, wire (Z, parallelingcoiuhictor 5i). thence through the convolutions ot w' (Z back to thenegative 'terminal ot the i; erator G; the closure ot this pick-up crtest circuit is oi relatively short duration, depending upon the timeof. contact between the shoe S and the surface of the ramp. Obviously,instead ot makiincr the return connection 'from the magnet E to theneger tive terminal of the generator G through the so-called detectorloop (Z, (Z, the indicated terminal oi the magnet E may be directlyconnected. tothe negative terminal ot' the generator. t will be noterthat the completion ot this test or pick-up circuit is dependent uponthe condition of the track relay TP. in the block ahead. lhould thisblock be occupied and the track relay TR short-circuited, the testcircuit aforesaid will be interrupted at the Contact Zi.

'fihe principal function ot the test or pickA up circuit is to cause thearmature is; ot the magnet ll to assume or maintain the same relationthe armature ot the t TR. in other words, vhen the arnrwure ot the trackrelay Tit is attracted. and the track loop circuit fw, w closed, and thetest or pick-up circuit is closed by the shoe engaing a ramp,electro-magnet pick up or attract its armature l., f closing a circuitfrom battery 6 through wire Zc, including normally closed push but tonpb, lamps L in parallel betn'ee-LA sections ot' wire Z0, coils ot a mathence through a holding magnet n' series with TM, thence to a springcontact ZJ, armature l, wire 0, back to the battery. it will be notedthat the armature r operates with the cores ot magnets E i so that, whenthe magnet lll attracts :irmature li, i. simultaneously closes thecircuit through the holding` mag et F and this latter magnet holdsarmature h. in its closed position until the circuit is subsequentlyinterrupted by operating the push button git. rl-Vhe closure oit thiscircuit through the mac;- net F also energizes trip magnet Thi?, whichattracts its armature a and breaks the pick up or test circuit atcontact a, thereby corr serving' the current from the generator G,

The purpose ot the pick-up or test circuit is to determine, first, by aconductivity test through the track loop T1150, the condition of thetrack circuit ahead and also to pic-l up the armature lever K and raiseit to safety position, under safety conditions`- by the momentary flowot current lrom the generator G through said circuit,y second, to closethe holding` circuit through magnet F and simultaneously break the testcircuit by the operation ot trip magnet TM, and third, to close a shuntcircuit to the loop Z, Z. included in circuits and C, which latterinclude the coil oi' the dill'erential relay and the valve holding'magnet "Jlil'ii respectiif'ely, said shunt circuit including wire sconnected to loop section Z, linger t to arma-- ture l, contact c2cooperatingi with said finger, and wire 82 connected with loop sectionZ. This shunt circuit to the loop Z,y Z, is closed before the circuitbreaker is actuated and, therefore-r serves to preserve the integrity otthe circuits through the coil 7 ot the diiierential relay and throughthe coils oi, the value holding; man-net, when said circuits wouldotherwise be interrupted by the circuit breaker CB when the latter isoperated by the shoe S engaging a ramp to break the loop Z, Z. V

The operation ot the ramp section et the syst-em is as follows: lWhenthe shoe Si engages the ramp lt in block Y and bloei' A is clear, theiirst effect is to close the pick- Lll) ini

up or test circuit between the shoe S and the surface of the ramp by wayof test loop TLO, contact Zz., track loop section fw', rail r, wheelsA2, and frame of the engine, to ground at G' thereon, etc., ashereinbefore described, thereby closing the shunt s, s2 about loop Z, Z'and circuit breaker CB' before the latter interrupts the circuits A andC at the loop Z, Z'. This produces no change in the normal relation ofthe coil 7 of relay DR and the valve holding magnet VHM, but causes thelighting of the lamps L to indicate that the circuits and apparatus ofthe ramp section are intact. The engineer breaks the circuit frombattery 6 through the holding magnet F at push button pb', therebyreleasing armature K and lneaking the shunt s, s2 to loop Z, Z'. Theseoperations are repeated when shoe i. engages ramp R, located near thehome point of block Y. lWhen block X is occupied and track loop w, w' isbroken at contact 7c and loop TLO is broken at contact it, theengagement of shoe S with the ramp R" is ineffective to close the testor pickup circuit, and shunt s, s2 remains open, with the result that,when the continued upward movement of shoe S opens circuit breaker CB',the circuits A and C are interrupted by said circuit breakerinterrupting tbe continuity of loop Z, Z', the brakes are applied,lan'ips L light up, and coil 8 attracts and holds armature 12 to holdcircuit C open until such time as said circuits A and C can be restoredby operating push button 7)?) to interrupt the circuit through coil 8 ofrelay DR, as hereinbefore explained.. After passing ramp R", theengineer operates said push button when the speed of thetrain has beenautomatically reduced, as described, thereby restoring circuits A and C.Upon reaching ramp R, the operations just described are repeated, and asecond amilieation of the brakes and operation of the signal lights Leffected, and the train is either automatically stopped, or may proceed,under properly reduced slpeed and absolute control, into the advanceblock X by the engineer again operating push button pb to break circuitB through the coil 8, thereby restoring circuits A and C to normallyclosed condition. Thus it will be seen that the functioning of the rampcontrolled section is wholly independent of the insulated track, orelectric controlled, section and, if the latter fails to operate., thetrain will be effectively protected by the ramp section of the dualisticsystem, and, conversely, if the ramp section fails, the insulated tracksection operates. Should both sections fail, the brakes are applied andthe train is stopped at once.

The two ramp and connected loop arrange-- ment. as shown in Figs. l and3, contemplates placing ramp R" the full braking distance back of thehome signal point and is rendered effective by connecting `the two rampsby a single wire, properly insulated and protected, which wireconstitutes a portion of the loop TL50. It will be Aevident, therefore,that the wayside installation of the ramp section is not onlyinexpensive to install and maintain, but reduces liability t-oderangement and damage of this portion of the apparatus to a minimum.Also, because of the fact that the engagement between the ramps and theshoe S carried by the locomotive, is only of sufficient duration toeffect the initial closing of the test or pickup circuit by contactbetween the shoe and the ramp, and second, to raise the shoe to opencircuit breaker CB', it is possible to employ relatively short ramps.

The alternate mode of obtaining remote control through the double rampinstallation in each block or section is that illustrated in Fig. 4, inwhich each block or section of the track is subdivided into two sectionsby means of insulated rail joints j2, jg, the rails of the subsectionadjacent ramp R" being represented by reference characters r2 and r3,respectively. In order to render this form of installation effective, itis necessary to interpose a so-called repeater circuit, which willrespond to and repeat the operation of the track relay TR ,in the nextsection ahead. The repeater circuit includes a battery X', one terminalof which is connected by conductor NZ to finger 7c?) of the track relayTR, which finger normally engages a` stationary contact re, which inturn is connected with track loop section te to rail r'. The otherterminal of the battery X' is connected to repeater relay LR, the otherterminal of which relay is connected by conductor rc to rail r. So longas track relay TR is en ergized, the circuit through the repeater relayLR will be completed and the armature of said relay will be attracted.When the track relay TR is short circiiiited, the circuit of therepeater relay LR is broken at Contact rc and the armature of the latterrelay falls away. The purpose of the repeater relay LR is to maintainthe saine operating conditions in the subsection of the block adjacentthe ramp R" as are maintained in the main section of the block, and alsoto maintain the integrity of the track circuit from the transformer T tothe relay TR of the given block, such as X. To effect these results, thefollowing connections' are em'- ployed; the joint in one rail isnormally bridged by a loop comprising wire to, armature finger Z',contact y', and wire to, and siniilarly, point is bridged by wire se,armature finger Z, contact y, and wire scZ. These bridging loops aremaintained intact so long repeater relay LR is energized. lhen, however,relay LR is deenergized by the short-circuiting of 'the track relay TRin the te, contact oc, linger Z, Wire ec, rai..

block ahead, it is also necessary to preserve Jthe continuity ot thetrack circuit in block il, which is effected by means of a conductor :teconnected to rail r and having therein a suitable condenser f/ andending' in a back contact Zic, engaged by finger J ot armature cirepeater relay LR, when the latter is deenergized; and a secondconductor d', havinga condenser g" and contact bc cooperating withlinger Z of the armature. Under the conditions linst indicated., thecomplete track circuit is follows: from one terminal or" transformer 'l`to rail i, Wire section r3, relay TR at the entrance ot block X, railr2, Wire to, linger Contact c, Wire tol, rail r', to the other terminalof the transformer T. The condensers lo, g will prevent the passage otdirect current but will. allou7 the alternafting` current to pass freelyto energize the trarlr relay TR, so long as block X is unoccupied. TheContact surface oli ramp l is connected to rail r as 'tollows: wire so,:linger Zo oi' arn'iature olf relay lil contact o, Wire so, to rail r2,so that, ivl'ien the shoe til oi` the locomotive engages ramp lt, thetest or piclrfup vcircuit on the locomotive will be closed from thegenerator G (Fig. l), Wire 50, shoe E, ramp lil, Wire so, armatureringer Zo, contact fv, wire so, rail r3, to enfgine Wheels and trame,Around at G" to r agnet lll bar-lr to generator (i, the engine carried'portions of the circuit being; the same as those hereinbeore described..lt the advance block is occupied, relays and lill are deenergized, andthe circuit last traced is brolren at contact o, ci relay LQ,consequently, when the shoe l engages the 'ramp lt, the test circuitwill not be` closed and the circuits and C on the locomotire will bebrolren at circuit breaker GB, thereby causing application cgt thebrakes and the bright illumination oli the signal lamps ll. illhen theramp is reached, the test or piclnup circuit is completed follows:generator wire 5l), shoe tl, ramp li, wire so connected to the contactsui-'tace ot the ramp, armature linger Zw. ot track relay 'llt of theblock sliced, tact it, track loop section to, rail 9"', ci ne wheels andtraine, to ground at G, magnet hl, baci( to generator, asbelfore. ltwill be apparent, therefore, that the employment of the subdivision oteach bloclr adjacent the ramp at the approach point of the block and theinterposition of the repeater relay circuit and the loop about theinsulated joints between the track sections of each block Will in no Wayinterfere With the normal functioning ci' the insulated traclr sectionof the system, or with the normal operation of vthe track circuit,including the source of alternating' current T and the track relay TR ineach block, but will, nevertheless, secure the certain and reliableoperation of the ramp section ot the system either to clos the piclnupor test circuit, as each ramp is engaged, to give a. delinite indicationwhen the block ahead is vloer, or, under danger conditions, to cause'the circuits l and C to be interrupted when each ramp is passed, by thenormal operation ot circuit breaker Uli, thereby causing;- applicationoit the brakes and the iiglitingr oit the signal lamps lo.

As an ancillary protective means to indicate the failure oli' einsulation ol" y the circuit wires, or the breakage o' the Wires, it isproposed to associate with all or any desired number ot the circuitWires or conductors, detector loops, which, upon failure ol theinsulrdion or disruption of any conductor, will short-circuit tbeparticular current source supplying` said conductor. l? or example, inFig. l the detector loop is associated with conductor 50 between thegenerator G and the shoe S, which conductor is subject to heavyvibrations and strains, said loop comprising a conductor wire .IZWrapped or Wound about insulated conductor 5l) and then brought baci; ina loop d pralleliug' aid conductor 5l? and lying adiacent to d, one endot' Wire (Zi beingconnected to the negative terminal of the generator (land the opposite end ot d beine; connected to one 'terminal of magnet Eolf the test circuit. Any serious impairment of the insulation onconductor 5l?, or a breako'l the latter, `which would involve a contactwith either wires d or ol, Will be evidenced immediately by theshort-circuiting olf the generator (l between the conductor 50 andeither one or both ot loop sections d, d. The saine protective eiiiectmay be obtained with respect to the conductors supplied by current frombattery 6, by connectingthe protective loop Wire one terminal ot battery(l and Windiug;v the Wire about the particular conductors to be guarded,as illustrated .in Fig. 5, in which Wire di? is con uected tothenegative pole oll battery (S and wound iu rons'aiilutions di; aboutconductor la in the holding circuit, thence continuing as loop il"paralleliugr Wire (7c, whence it is passed in successive windings orconvolutions as di' about loop Vwires l and l, thence perallelini`conductor 23 in a section d and connected to one or more ol the metalliccups li/l o'j the truclr insulation, 'whence a linal section di isWound. about conductor rElie failure olf insulation el any oit the Wiresassociated with the conductor loops will be evidenced at once by theshort-circuiting o the battery 6 and the release ot the brano holdingmagnet, which would apply the brakes. llt will be understood, oi course,that similar protective loops be appLied to all ot the circuit Wiresinvolved in the system but, as the Wires or conductors hereto'lorereferred to are the principal ones which liable to damage orimpair-nient,

under normal conditions of use, the protective loops have been indicatedas applied only to such wires or conductors.

From the foregoing description, it will be apparent that the instantinvention involves a simple and reliable dualistic system of traincontrol, in which both elements of the system will be eil'cctive toaccurately and reliably indicate safety conditions at all times, thatwill with equal reliability and effectiveness cooperate to indicatedanger conditions and irst reduce the speed of the train and thenautomatically stop the same, under danger conditions7 unless theengineer assumes control after the desired reduction in `the speed hasbeen made, each of the separate elements of the dualistic system beingso far inde ndent of the other as to function perfect y in the case offailure of the other. In case both elements fail, the train Will beautomatically stopped.

What I claim as new, and desire to secure by Letters Patent, is

1. The combination with a train carried electro-magnet governing means,of a normally closed circuit therefor, and a series of all-rail trackcircuits, a dual system of control and operation interposed between saidtrack circuits and said electro-magnetic governing` means to act on saidmagnet governing means, one system operating according to an electricalmode of operation and the other according to an electro-mechanical modeof operation and both responding under the iniluence of a ygiven trackcircuit.

2. A plurality of all-rail track circuits arranged in immediate relationto each other, a normally closed circuit carried by a vehicle movable onthe rails, including the rails and a track loop of negligibleresistanceat a predetermined vpoint and directly controlled by the adjacent trackcircuit, a second closed circuit including vehicle control mechanismcontrolled by the first mentioned circuit, a normally open circuitcarried in part by the vehicle and in part by the trackway and includingthe rails and the track loop aforesaid, and means carried by the vehiclefor closing said open circuit at a predetermined point to firstestablish an alternative closed path for said second closed circuit andthen to interrupt the original path of said second circuit under safetyconditions.

3. A. plurality of all-rail track circuits arranged in immediaterelation to each other, a normally closed circuit carried by a vehiclemovable on the rails, including the rails and a track loop of negligibleresistance at a predetermined point and directly controlled by theadjacent track circuit, a second closed circuit including vehiclecontrol mechanism controlled 'by the first mentioned circuit, a normallyopen circuit carried in part by the vehicle and in part by the trackwayand including the rails and the track loop aforesaid, a mechanicalcircuit ybreaker in said second circuit, and means carried by thevehicle for closing said open circuit at a predetermined point to closea shunt around said circuit breaker to maintain the integrity of saidsecond circuit and then to operate said circuit breaker to interrupt theoriginal path of said second circuit under safety conditions.

4. The combination with a vehicle carried. normally closed circuit, andan electro-magnet governing means included therein, of a normallyclosedtrack connected control circuit operatively associated with therst mentioned circuit, an all-rail track circuit, a point of resistanceon the track that is presented to and withdrawn from the controlcircuit, under the influence of the track circuit, track engagingmechanically operated means for breaking the iirst mentioned circuit,and a normally open vehicle carried circuit associated in controllingrelationship with the first mentioned circuit and controlled by the,track circuit under safety conditions to close the first mentionedcircuit against the mechanically operated means.

5. The combination with a vehicle carried normally closed circuit, andan electro-magnet governing means included therein, of a normally closedtrack connected control circuit operatively associated With the firstmentioned circuit, an all-rail track circuit, a point of resistance onthe track that ispresented to and withdrawn from. the control circuitunder the influence of the track circuit, track engaging mechanicallyoperated means for breaking the iirst mentioned circuit, a normally openholding circuit, and a normally open control circuit co-operativelyassociated with the first mentioned circuit and controlled by the trackcircuit under safety conditions to close the first mentioned circuitagainst the action of the mechanically operated means.

6. The combination with a vehicle carried normally closed circuit, andan electro-magnet governing means included therein, of multiple controlmeans operatively i associated therewith, ,embracing a normally closedcontrol circuit, a normally open controlling circuit and a mechanicallyoperated means interposed between the iiirst mentioned circuit and thetrack, an all-rail track circuit, controlling devices at traffic controlpoints governed bythe condition of the track circuit for opening saidnormally closed circuit through one of said controlling devices andseparately opening the same through the action of the mechanicallyoperated means under danger conditions both of said controlling circuitscoi-operating under safety conditions to maintain the first mentionedcircuit closed under the influence of the track circuit against 4theaction of the mechanically operated means.

7. An automatic train control system of a dualistic character having incombination with a normally closed circuit an included electro-magnetcarried on a vehicle, of mechanically operated means for opening saidcircuit, embracing members along the track and a member carried by thevehicle disposed in running position to engage said track members, anall-rail track circuit, ve-

hicle carried control circuits interposed between the first mentionedcircuit and the track circuit and controlled by the latter atpredetermined points one of said control circuits under safetyconditions holding closed the lirstmentioned circuit while the otherunder like conditions automatically places a compensating shunt on thatportion of the rst mentioned circuit about to be broken by themechanically operated means.

8. ln a dualistic train control system, a vehicle carried workingcircuit and a cooperatively associated control circuit both of which areresponsive to a cessation of current said control circuit having twosets of normally closed terminals arranged in series, one of said setsbeing vehicle carried while the other is arranged in operative relationto the track, means depending upon the movement of said vehicle to opensaid terminals under danger conditions at prede-- termined points, aloop of negligible resistance for bridging each of said terminals undersafety conditions to form a compensating pathway, a vehicle carriedtransient circuit for controlling the loop for bridging the vehiclecarried terminals, an all-rail track circuit for controlling thetransient circuit and the other loop to render inoperative the workingcircuit under safety conditions.

9. In a dualistic train control system, a vehicle carried workingcircuit and a co-operatively associated control circuit both beingresponsive to a cessation of current said control circuit having twosets of normally closed terminals arranged in series in the controlcircuit one of which is on the track and the other on the vehicle, meansdepending upon the movement of said vehicle to open the terminals ofboth under danger conditions at predetermined points, an allrail trackcircuit, and partial circuit devices controlled by the track circuit forproviding a compensating pathway for the respectiver sets of terminalsunder safety conditions to render the working and control circuitsunaected under safety conditions, aty

such points.

l0. ln a dualistic train control system, a vehicle carried workingcircuit and a cooperatively associated control circuit, both beingresponsive to a cessation of current, said control circuit havingincluded at three different points circuit making-and--breaking devicestwo of which are vehicle carried while the other is arranged in directoperative relation to the track, one vehicle carried maaier circuit naking-and-breaking device and that in operative relation to the trackbeing opened by the movement of the vehicle past a given point in thetrack under danger conditions, an incomplete ti ansient control circuiteitending substantially in parallel relation with the first mentionedcontrol circuit and that is responsive to closure to cause the closureof the other vehicle carried makingand-breaking device, and an ail-railtrack circuit vfor controlling the closure of the transient circuit andthe breil 'ng-and-making device arranged in operative relation to thetrack nder safety conditions.

il. ln a dualistic train control system, a vehicle carried workingcircuit and a co-operatively associated control circuit both being`responsive to a cessation of currentsaid control circuit having two setsnormall y closed terminals arranged in series one of which is vehiclecarried while the otl er is arranged in operative relation to the track,means depending upon the movement of the vehicle to open said terminalsat predetermined points, a transient co-ordinate control circuitresponsive to closure thereof to insert a low resistance shunt acrossthe gap of the vehicle carried terminals, a track loop for closing thetransient control circuit and the track connected terminals of the firstmentioned control circuit, and an all-rail track circ iit forcontrolling said track loop, the whole arranged to render the `firstmentioned control. circuit and the working circuit inperative unoersafety conditions.

12. ln a dual system of train control, a cab carried working circuit anda co-operatively associated control circuit that is track connected,both of said circuits .having a common source of electric energy andworking on the closed circuit princinle, and anotl er control circuitco-operating with said working circuit that is fed by a diiferent sourceof electric energy and possesses a different character of operation, amechanically operated means for breaking said working circuit and afixed member on the track for actuating said mechanically operatedmeans, and an all-rail track circuit for simultaneously controlling saidcontrol circuits to lhold the working circuit closed against the actionof the mechanically operated means under safety conditions.

13. lin a dualistic train control sv, i plurality of all rail trackcircuits, each including an insulated track section, a source of currentand a relay; a control circuit carried by the vehicle; partial circuitdevices co-operatively associated with the track and directly controlledby said relay to determine the condition of said control circuit; asecond circuit on the vehicle normally maintained closed by said controlcircuit; and train control mechanism rendered operative upon cessationof current in any of said cirloo lli

cuits, in combination with a normally incomplete transient controlcircuit, partial circuit devices therefor co-operatively associated withthe track circuit and directly controlled by the track relay todetermine the condition of the first mentioned control circuit and thesecond circuit.

14. In a dualistic train control system, an insulated track section, asource of electric energy and a relay: a control circuit carried by avehicle; partial circuit elements for opening and closing said circuitthat are directly controlled by said relay; a second circuit on thevehicle normally maintained closed by said control circuit; and traincontrol mechanism made operative upon ccssation of current in any ofsaid circuits, in combination with a mechanical circuit makerand-breakerthat engages a part on the track at predetermined points for the openingof the second circuit every time the said breaker engages a part on thetrack, a normally incomplete transient control circuit carried on thevehicle, a partial circuit therefor cooperatively associated with thetrack relay to determine the condition of said circuit, and meanscontrolled by said transient control circuit for inserting acompensating shunt across the break about to be effected in the secondcircuit by the circuit breaker under safety conditions, and a thirdsignal and holding circuit that is initially closed under the influenceof the transient control circuit and the track relay for maintainingsaid compensatingk shunt in closed position.

15. A railway cab signal and cqntrol system, comprising a signal andbrake controlling circuit, a source of electric energy therefor, `anall-rail track circuit, and means comprising two independently operatingcircuits interposed between said track circuit and the first mentionedcircuit that are controlled by the track circuit to maintain theintegrity of the first mentioned circuit under safety conditions attraffic control points, anda mechanically operated means and a point ofresistance operating respectively to effect an opening of the firstmentioned circuit under danger conditions.

16. In a dualistic train control system, an insulated track section, asource of current and a relay, another source of current and a controlcircuit carried by the vehicle, partial circuit elements Ico-opcrativelyassociated with the track section and directlv controlled by said relayto determine the condition of said control circuit; a second circuit onthe vehicle normally closed through the control circuit; train controlmechanism rendered operative upon the cessation of current in any ofsaid circuits, in combination with a mechanical circuitmaker-and-breaker, a fixed member along the track for engaging andoperating the latter during the movement of the vehicle to open thesecond circuit every time it passes said point, a second source ofcurrent on the vehicle, a vehicle carried partial circuit co-operativelyassociated with the relay to complete said circuit with the inclusion ofthe second source of current under safety conditions said partialcircuit being responsive under closure to effect a shunt around thepoint in the second circuit subject to the mechanical breakage before itis effected, and a holding and signal circuit in parallel with the firsttwo mentioned circuits that is fed by the first mentioned source ofcurrent which is established by the partial circuit under safetycondition through the infiuence of the track relay.

17. In a dualistic train control system, a normally closed workingcircuit, a signal and train control mechanism rendered operative uponcessation of current in said working circuit, a normally closed controlcircuit for determining the condition of said working circuit, amechanical make-and-break device for breaking and making the working andcontrol circuits, a fixed member along the track for operating thedevice to break the working and control circuits every time the fixedmember is encountered, a normally open control circuit responsive toclosure to effect a compensating shunt across the break effected by themechanical circuit breaker to preserve the integrity of the Workingcircuit, .a signal and holding circuit that is closed upon the closureof the open control circuit to retain the compensating shunt whenestablished, an al1-rail track circuit having a source of electricenergy and a relay, and partial circuit devices co-operativelyassociated with the track circuit for determining the condition of thenormally closed and normally open control circuits respectively.

18. The safety system for railway trains hereinbefore described,comprising two train carried co-ordinate circuit members, a trackcircuit from which they are disconnected under danger conditions and towhich they are connected under safety conditions at predeterminedpoints, a normally closed( brake control circuit carried by the traincontrolled respectively by said co-ordinate circuit members, amechanically operated means interposed between said brake control andtrack circuits that acts to mechanically break said control circuit whensaid co-ordinate circuit members are disconnected from the track circuitunder danger conditions and means associated with one of saidco-ordinate circuit members to maintain the other coordinate circuitmember closed against theaction of the mechanically operated means undersafety conditions.

In testimony whereof I aix my signature.

JOSEPH WHITMAN BUELL.

